/*
 * Created on Dec 4, 2004
 * Created by Alon Rohter
 * Copyright (C) Azureus Software, Inc, All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 */

package com.aelitis.azureus.core.networkmanager.impl.tcp;

import java.io.IOException;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;

import org.gudy.azureus2.core3.logging.LogIDs;
import org.gudy.azureus2.core3.util.AEThread;
import org.gudy.azureus2.core3.util.Debug;

import com.aelitis.azureus.core.networkmanager.VirtualChannelSelector;

/**
 * Virtual server socket channel for listening and accepting incoming connections.
 */
public class VirtualAcceptSelector {
    private static final VirtualAcceptSelector singleton = new VirtualAcceptSelector();

    public static VirtualAcceptSelector getSingleton() {
        return (singleton);
    }

    private static final LogIDs LOGID = LogIDs.NWMAN;

    private final VirtualChannelSelector accept_selector = new VirtualChannelSelector("Accepter", VirtualChannelSelector.OP_ACCEPT, false);

    protected VirtualAcceptSelector() {
        AEThread select_thread = new AEThread("Accept Selector") {
            public void runSupport() {
                while (true) {

                    try {
                        accept_selector.select(50);

                    } catch (Throwable e) {

                        Debug.printStackTrace(e);
                    }
                }
            }
        };

        select_thread.setDaemon(true);
        select_thread.start();
    }

    public void register(ServerSocketChannel channel, final AcceptListener listener) {
        accept_selector.register(channel, new VirtualChannelSelector.VirtualAcceptSelectorListener() {
            public boolean selectSuccess(VirtualChannelSelector selector, ServerSocketChannel sc, Object attachment) {
                try {
                    SocketChannel new_channel = sc.accept();

                    if (new_channel == null) {

                        return (false);
                    }

                    try {
                        new_channel.configureBlocking(false);

                    } catch (IOException e) {

                        new_channel.close();

                        throw (e);
                    }

                    listener.newConnectionAccepted(new_channel);

                    return (true);

                } catch (IOException e) {

                    Debug.printStackTrace(e);

                    return (true);
                }
            }

            public void selectFailure(VirtualChannelSelector selector, ServerSocketChannel sc, Object attachment, Throwable msg) {
                Debug.printStackTrace(msg);
            }
        }, null);
    }

    public void cancel(ServerSocketChannel channel) {
        accept_selector.cancel(channel);
    }

    /**
     * Listener notified when a new incoming connection is accepted.
     */

    public interface AcceptListener {
        /**
         * The given connection has just been accepted.
         * 
         * @param channel
         *            new connection
         */
        public void newConnectionAccepted(SocketChannel channel);
    }
}
